Exposure to bisphenol A (BPA) significantly alters the development of oocytes and future ova in women, possibly diminishing the fertility of their offspring and increasing the risk of Down syndrome in following generations, according to a study in Human Reproduction (October 2011, Vol. 26:10, pp. 2807-2818).
Researchers at Autonomous University of Barcelona (UAB), in collaboration with the Vall d'Hebron Hospital Fetal Tissue Bank, the Hospital Vall d'Hebron Department of Gynaecology and Obstetrics, the Research Unit of Paediatric Endocrinology at Vall d'Hebron Research Institute, and others, analyzed the effects of BPA in an in vitro culture of ovaries.
The research was carried out with a culture of 21,570 in vitro oocytes. Oocytes were cultured for seven, 14, or 21 days in different environments, with the presence of BPA and in control cultures without the substance.
The researchers found that BPA exposure in concentration levels permitted by health authorities is harmful to the fetus. In addition, BPA reduces the number of oocytes (cells which develop into ova) and therefore can affect negatively a woman's fertility and double the risk of chromosome exchange during the cell division process, they noted. Specific observations of chromosome 21 in the development of 90 oocytes revealed that exposure to BPA could increase the risk of Down syndrome in the future offspring of the fetus.
"According to our results, BPA does not directly affect the fertility of pregnant women, but that of their daughters and granddaughters. It is a multigenerational effect," stated UAB professor Montserrat Garcia Caldés, the director of the research, in a press release. "The increase in oocyte mortality in the fetus could diminish ovarian reserve numbers and the quality of the future mother's ova. At the same time, alterations in the recombination of chromosomes in the process of cell division increase the possibility of numerical alterations."
Concentration levels applied in the experiments were within the safety limits marked by European and U.S. authorities, the researchers noted. The research therefore suggests that staying within legal limits does not imply that exposure to the substance is innocuous, they emphasized.
The study adds to the growing body of evidence pointing to the negative health effects of BPA, a synthetic chemical with estrogenic properties that is used in various products, including dental sealants. In animal studies, exposure to BPA early in life has been shown to prompt hormonal and reproductive issues, including abnormalities in the early development of the brain, prostate gland, and breast tissues.
